1. Field of the Invention
The present invention relates to an original conveying apparatus, a light amount adjustment method for a light-emitting section thereof, an image forming apparatus, a control method therefor, a storage control device, a storage control method, and a storage medium. In particular, the present invention relates to an original conveying apparatus of an image forming apparatus such as a copier or a laser beam printer that conveys originals to an image reading section of the image forming apparatus, a light amount adjustment method for a light-emitting section of the original conveying apparatus, the image forming apparatus, a control method for the image forming apparatus, a storage control device, a storage control method, and a storage medium storing a program for implementing the storage control method.
2. Description of the Related Art
Conventionally, an ADF(Auto document feeder) or the like is used as an original conveying apparatus of an image forming apparatus such as a copier or a laser beam printer, in which originals are separated sheet by sheet from a stack of originals set in an original tray, the separated original being conveyed to an image reading section of the image forming apparatus, where image formation is carried out, and then the separated originals are discharged from the original conveying apparatus into a discharge tray. To carry out this operation, the original conveying apparatus is provided with a large number of sensors which sense the position of an original currently being conveyed, and whether or not there are still originals set in the original tray. Moreover, a large number of sensors including ones for detecting recording sheets are also provided on the main body side of the image forming apparatus. Known types of such sensors include flag type sensors, and optical sensors that are comprised of a light-emitting section and a light-receiving section.
In the case of an optical sensor, the amount of light from the light-emitting section may drop due to variations between sensor elements or the lifetime being reached, and thus to maintain the performance of the sensor it is necessary to carry out adjustments. An EEPROM or the like is used as a storage medium for storing adjustment values even when the power supply is off.
However, in the case of a conventional apparatus such as an original conveying apparatus or an image forming apparatus having one or more optical sensors as described above, problems such as the following can be envisaged.
The light-emitting element (generally an LED) used in the light-emitting section of an optical sensor has a lifetime, and the amount of light emitted drops due to aging. Moreover, if there is paper dust, dirt or the like on the surface of a sensor element, then there will be a drop in the amount of light reaching the light-receiving section. To maintain the performance of an optical sensor over a prolonged period of time, it is thus necessary to adjust the amount of light emitted at regular time intervals.
The correction value of the light emission amount of an optical sensor when this light emission amount has been adjusted is written into a nonvolatile storage medium such as an EEPROM so as to be kept even after the power supply has been turned off, but there is a limit on the number of times that such a nonvolatile storage medium can be written. Thus, if writing is carried out frequently, then there is a chance that this limit may be reached before the lifetime of the device is reached.
It is thus desirable to reduce as far as possible the number of times that data is written to such a storage medium that is capable of storing data such as correction values used in correction (adjustment) processing for maintaining proper output processing but for which the number of times that data can be written is limited, thus lengthening the lifetime of the storage medium and eliminating the occurrence of inconvenient situations such as it being impossible to maintain proper output processing.